2 * Copyright (C) 2008 Red Hat, Inc., Eric Paris <eparis@redhat.com>
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2, or (at your option)
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
14 * You should have received a copy of the GNU General Public License
15 * along with this program; see the file COPYING. If not, write to
16 * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
20 * fsnotify inode mark locking/lifetime/and refcnting
23 * The group->recnt and mark->refcnt tell how many "things" in the kernel
24 * currently are referencing the objects. Both kind of objects typically will
25 * live inside the kernel with a refcnt of 2, one for its creation and one for
26 * the reference a group and a mark hold to each other.
27 * If you are holding the appropriate locks, you can take a reference and the
28 * object itself is guaranteed to survive until the reference is dropped.
31 * There are 3 locks involved with fsnotify inode marks and they MUST be taken
32 * in order as follows:
36 * mark->connector->lock
38 * group->mark_mutex protects the marks_list anchored inside a given group and
39 * each mark is hooked via the g_list. It also protects the groups private
40 * data (i.e group limits).
42 * mark->lock protects the marks attributes like its masks and flags.
43 * Furthermore it protects the access to a reference of the group that the mark
44 * is assigned to as well as the access to a reference of the inode/vfsmount
45 * that is being watched by the mark.
47 * mark->connector->lock protects the list of marks anchored inside an
48 * inode / vfsmount and each mark is hooked via the i_list.
50 * A list of notification marks relating to inode / mnt is contained in
51 * fsnotify_mark_connector. That structure is alive as long as there are any
52 * marks in the list and is also protected by fsnotify_mark_srcu. A mark gets
53 * detached from fsnotify_mark_connector when last reference to the mark is
54 * dropped. Thus having mark reference is enough to protect mark->connector
55 * pointer and to make sure fsnotify_mark_connector cannot disappear. Also
56 * because we remove mark from g_list before dropping mark reference associated
57 * with that, any mark found through g_list is guaranteed to have
58 * mark->connector set until we drop group->mark_mutex.
61 * Inode marks survive between when they are added to an inode and when their
62 * refcnt==0. Marks are also protected by fsnotify_mark_srcu.
64 * The inode mark can be cleared for a number of different reasons including:
65 * - The inode is unlinked for the last time. (fsnotify_inode_remove)
66 * - The inode is being evicted from cache. (fsnotify_inode_delete)
67 * - The fs the inode is on is unmounted. (fsnotify_inode_delete/fsnotify_unmount_inodes)
68 * - Something explicitly requests that it be removed. (fsnotify_destroy_mark)
69 * - The fsnotify_group associated with the mark is going away and all such marks
70 * need to be cleaned up. (fsnotify_clear_marks_by_group)
72 * This has the very interesting property of being able to run concurrently with
73 * any (or all) other directions.
77 #include <linux/init.h>
78 #include <linux/kernel.h>
79 #include <linux/kthread.h>
80 #include <linux/module.h>
81 #include <linux/mutex.h>
82 #include <linux/slab.h>
83 #include <linux/spinlock.h>
84 #include <linux/srcu.h>
86 #include <linux/atomic.h>
88 #include <linux/fsnotify_backend.h>
91 #define FSNOTIFY_REAPER_DELAY (1) /* 1 jiffy */
93 struct srcu_struct fsnotify_mark_srcu;
94 struct kmem_cache *fsnotify_mark_connector_cachep;
96 static DEFINE_SPINLOCK(destroy_lock);
97 static LIST_HEAD(destroy_list);
98 static struct fsnotify_mark_connector *connector_destroy_list;
100 static void fsnotify_mark_destroy_workfn(struct work_struct *work);
101 static DECLARE_DELAYED_WORK(reaper_work, fsnotify_mark_destroy_workfn);
103 static void fsnotify_connector_destroy_workfn(struct work_struct *work);
104 static DECLARE_WORK(connector_reaper_work, fsnotify_connector_destroy_workfn);
106 void fsnotify_get_mark(struct fsnotify_mark *mark)
108 WARN_ON_ONCE(!refcount_read(&mark->refcnt));
109 refcount_inc(&mark->refcnt);
112 static __u32 *fsnotify_conn_mask_p(struct fsnotify_mark_connector *conn)
114 if (conn->type == FSNOTIFY_OBJ_TYPE_INODE)
115 return &fsnotify_conn_inode(conn)->i_fsnotify_mask;
116 else if (conn->type == FSNOTIFY_OBJ_TYPE_VFSMOUNT)
117 return &fsnotify_conn_mount(conn)->mnt_fsnotify_mask;
121 __u32 fsnotify_conn_mask(struct fsnotify_mark_connector *conn)
123 if (WARN_ON(!fsnotify_valid_obj_type(conn->type)))
126 return *fsnotify_conn_mask_p(conn);
129 static void __fsnotify_recalc_mask(struct fsnotify_mark_connector *conn)
132 struct fsnotify_mark *mark;
134 assert_spin_locked(&conn->lock);
135 /* We can get detached connector here when inode is getting unlinked. */
136 if (!fsnotify_valid_obj_type(conn->type))
138 hlist_for_each_entry(mark, &conn->list, obj_list) {
139 if (mark->flags & FSNOTIFY_MARK_FLAG_ATTACHED)
140 new_mask |= mark->mask;
142 *fsnotify_conn_mask_p(conn) = new_mask;
146 * Calculate mask of events for a list of marks. The caller must make sure
147 * connector and connector->obj cannot disappear under us. Callers achieve
148 * this by holding a mark->lock or mark->group->mark_mutex for a mark on this
151 void fsnotify_recalc_mask(struct fsnotify_mark_connector *conn)
156 spin_lock(&conn->lock);
157 __fsnotify_recalc_mask(conn);
158 spin_unlock(&conn->lock);
159 if (conn->type == FSNOTIFY_OBJ_TYPE_INODE)
160 __fsnotify_update_child_dentry_flags(
161 fsnotify_conn_inode(conn));
164 /* Free all connectors queued for freeing once SRCU period ends */
165 static void fsnotify_connector_destroy_workfn(struct work_struct *work)
167 struct fsnotify_mark_connector *conn, *free;
169 spin_lock(&destroy_lock);
170 conn = connector_destroy_list;
171 connector_destroy_list = NULL;
172 spin_unlock(&destroy_lock);
174 synchronize_srcu(&fsnotify_mark_srcu);
177 conn = conn->destroy_next;
178 kmem_cache_free(fsnotify_mark_connector_cachep, free);
182 static void *fsnotify_detach_connector_from_object(
183 struct fsnotify_mark_connector *conn,
186 struct inode *inode = NULL;
189 if (conn->type == FSNOTIFY_OBJ_TYPE_DETACHED)
192 if (conn->type == FSNOTIFY_OBJ_TYPE_INODE) {
193 inode = fsnotify_conn_inode(conn);
194 inode->i_fsnotify_mask = 0;
195 atomic_long_inc(&inode->i_sb->s_fsnotify_inode_refs);
196 } else if (conn->type == FSNOTIFY_OBJ_TYPE_VFSMOUNT) {
197 fsnotify_conn_mount(conn)->mnt_fsnotify_mask = 0;
200 rcu_assign_pointer(*(conn->obj), NULL);
202 conn->type = FSNOTIFY_OBJ_TYPE_DETACHED;
207 static void fsnotify_final_mark_destroy(struct fsnotify_mark *mark)
209 struct fsnotify_group *group = mark->group;
211 if (WARN_ON_ONCE(!group))
213 group->ops->free_mark(mark);
214 fsnotify_put_group(group);
217 /* Drop object reference originally held by a connector */
218 static void fsnotify_drop_object(unsigned int type, void *objp)
221 struct super_block *sb;
225 /* Currently only inode references are passed to be dropped */
226 if (WARN_ON_ONCE(type != FSNOTIFY_OBJ_TYPE_INODE))
231 if (atomic_long_dec_and_test(&sb->s_fsnotify_inode_refs))
232 wake_up_var(&sb->s_fsnotify_inode_refs);
235 void fsnotify_put_mark(struct fsnotify_mark *mark)
237 struct fsnotify_mark_connector *conn;
239 unsigned int type = FSNOTIFY_OBJ_TYPE_DETACHED;
240 bool free_conn = false;
242 /* Catch marks that were actually never attached to object */
243 if (!mark->connector) {
244 if (refcount_dec_and_test(&mark->refcnt))
245 fsnotify_final_mark_destroy(mark);
250 * We have to be careful so that traversals of obj_list under lock can
251 * safely grab mark reference.
253 if (!refcount_dec_and_lock(&mark->refcnt, &mark->connector->lock))
256 conn = mark->connector;
257 hlist_del_init_rcu(&mark->obj_list);
258 if (hlist_empty(&conn->list)) {
259 objp = fsnotify_detach_connector_from_object(conn, &type);
262 __fsnotify_recalc_mask(conn);
264 mark->connector = NULL;
265 spin_unlock(&conn->lock);
267 fsnotify_drop_object(type, objp);
270 spin_lock(&destroy_lock);
271 conn->destroy_next = connector_destroy_list;
272 connector_destroy_list = conn;
273 spin_unlock(&destroy_lock);
274 queue_work(system_unbound_wq, &connector_reaper_work);
277 * Note that we didn't update flags telling whether inode cares about
278 * what's happening with children. We update these flags from
279 * __fsnotify_parent() lazily when next event happens on one of our
282 spin_lock(&destroy_lock);
283 list_add(&mark->g_list, &destroy_list);
284 spin_unlock(&destroy_lock);
285 queue_delayed_work(system_unbound_wq, &reaper_work,
286 FSNOTIFY_REAPER_DELAY);
290 * Get mark reference when we found the mark via lockless traversal of object
291 * list. Mark can be already removed from the list by now and on its way to be
292 * destroyed once SRCU period ends.
294 * Also pin the group so it doesn't disappear under us.
296 static bool fsnotify_get_mark_safe(struct fsnotify_mark *mark)
301 if (refcount_inc_not_zero(&mark->refcnt)) {
302 spin_lock(&mark->lock);
303 if (mark->flags & FSNOTIFY_MARK_FLAG_ATTACHED) {
304 /* mark is attached, group is still alive then */
305 atomic_inc(&mark->group->user_waits);
306 spin_unlock(&mark->lock);
309 spin_unlock(&mark->lock);
310 fsnotify_put_mark(mark);
316 * Puts marks and wakes up group destruction if necessary.
318 * Pairs with fsnotify_get_mark_safe()
320 static void fsnotify_put_mark_wake(struct fsnotify_mark *mark)
323 struct fsnotify_group *group = mark->group;
325 fsnotify_put_mark(mark);
327 * We abuse notification_waitq on group shutdown for waiting for
328 * all marks pinned when waiting for userspace.
330 if (atomic_dec_and_test(&group->user_waits) && group->shutdown)
331 wake_up(&group->notification_waitq);
335 bool fsnotify_prepare_user_wait(struct fsnotify_iter_info *iter_info)
339 fsnotify_foreach_obj_type(type) {
340 /* This can fail if mark is being removed */
341 if (!fsnotify_get_mark_safe(iter_info->marks[type]))
346 * Now that both marks are pinned by refcount in the inode / vfsmount
347 * lists, we can drop SRCU lock, and safely resume the list iteration
348 * once userspace returns.
350 srcu_read_unlock(&fsnotify_mark_srcu, iter_info->srcu_idx);
355 for (type--; type >= 0; type--)
356 fsnotify_put_mark_wake(iter_info->marks[type]);
360 void fsnotify_finish_user_wait(struct fsnotify_iter_info *iter_info)
364 iter_info->srcu_idx = srcu_read_lock(&fsnotify_mark_srcu);
365 fsnotify_foreach_obj_type(type)
366 fsnotify_put_mark_wake(iter_info->marks[type]);
370 * Mark mark as detached, remove it from group list. Mark still stays in object
371 * list until its last reference is dropped. Note that we rely on mark being
372 * removed from group list before corresponding reference to it is dropped. In
373 * particular we rely on mark->connector being valid while we hold
374 * group->mark_mutex if we found the mark through g_list.
376 * Must be called with group->mark_mutex held. The caller must either hold
377 * reference to the mark or be protected by fsnotify_mark_srcu.
379 void fsnotify_detach_mark(struct fsnotify_mark *mark)
381 struct fsnotify_group *group = mark->group;
383 WARN_ON_ONCE(!mutex_is_locked(&group->mark_mutex));
384 WARN_ON_ONCE(!srcu_read_lock_held(&fsnotify_mark_srcu) &&
385 refcount_read(&mark->refcnt) < 1 +
386 !!(mark->flags & FSNOTIFY_MARK_FLAG_ATTACHED));
388 spin_lock(&mark->lock);
389 /* something else already called this function on this mark */
390 if (!(mark->flags & FSNOTIFY_MARK_FLAG_ATTACHED)) {
391 spin_unlock(&mark->lock);
394 mark->flags &= ~FSNOTIFY_MARK_FLAG_ATTACHED;
395 list_del_init(&mark->g_list);
396 spin_unlock(&mark->lock);
398 atomic_dec(&group->num_marks);
400 /* Drop mark reference acquired in fsnotify_add_mark_locked() */
401 fsnotify_put_mark(mark);
405 * Free fsnotify mark. The mark is actually only marked as being freed. The
406 * freeing is actually happening only once last reference to the mark is
407 * dropped from a workqueue which first waits for srcu period end.
409 * Caller must have a reference to the mark or be protected by
410 * fsnotify_mark_srcu.
412 void fsnotify_free_mark(struct fsnotify_mark *mark)
414 struct fsnotify_group *group = mark->group;
416 spin_lock(&mark->lock);
417 /* something else already called this function on this mark */
418 if (!(mark->flags & FSNOTIFY_MARK_FLAG_ALIVE)) {
419 spin_unlock(&mark->lock);
422 mark->flags &= ~FSNOTIFY_MARK_FLAG_ALIVE;
423 spin_unlock(&mark->lock);
426 * Some groups like to know that marks are being freed. This is a
427 * callback to the group function to let it know that this mark
430 if (group->ops->freeing_mark)
431 group->ops->freeing_mark(mark, group);
434 void fsnotify_destroy_mark(struct fsnotify_mark *mark,
435 struct fsnotify_group *group)
437 mutex_lock_nested(&group->mark_mutex, SINGLE_DEPTH_NESTING);
438 fsnotify_detach_mark(mark);
439 mutex_unlock(&group->mark_mutex);
440 fsnotify_free_mark(mark);
444 * Sorting function for lists of fsnotify marks.
446 * Fanotify supports different notification classes (reflected as priority of
447 * notification group). Events shall be passed to notification groups in
448 * decreasing priority order. To achieve this marks in notification lists for
449 * inodes and vfsmounts are sorted so that priorities of corresponding groups
452 * Furthermore correct handling of the ignore mask requires processing inode
453 * and vfsmount marks of each group together. Using the group address as
454 * further sort criterion provides a unique sorting order and thus we can
455 * merge inode and vfsmount lists of marks in linear time and find groups
456 * present in both lists.
458 * A return value of 1 signifies that b has priority over a.
459 * A return value of 0 signifies that the two marks have to be handled together.
460 * A return value of -1 signifies that a has priority over b.
462 int fsnotify_compare_groups(struct fsnotify_group *a, struct fsnotify_group *b)
470 if (a->priority < b->priority)
472 if (a->priority > b->priority)
479 static int fsnotify_attach_connector_to_object(fsnotify_connp_t *connp,
482 struct inode *inode = NULL;
483 struct fsnotify_mark_connector *conn;
485 conn = kmem_cache_alloc(fsnotify_mark_connector_cachep, GFP_KERNEL);
488 spin_lock_init(&conn->lock);
489 INIT_HLIST_HEAD(&conn->list);
492 if (conn->type == FSNOTIFY_OBJ_TYPE_INODE)
493 inode = igrab(fsnotify_conn_inode(conn));
495 * cmpxchg() provides the barrier so that readers of *connp can see
496 * only initialized structure
498 if (cmpxchg(connp, NULL, conn)) {
499 /* Someone else created list structure for us */
502 kmem_cache_free(fsnotify_mark_connector_cachep, conn);
509 * Get mark connector, make sure it is alive and return with its lock held.
510 * This is for users that get connector pointer from inode or mount. Users that
511 * hold reference to a mark on the list may directly lock connector->lock as
512 * they are sure list cannot go away under them.
514 static struct fsnotify_mark_connector *fsnotify_grab_connector(
515 fsnotify_connp_t *connp)
517 struct fsnotify_mark_connector *conn;
520 idx = srcu_read_lock(&fsnotify_mark_srcu);
521 conn = srcu_dereference(*connp, &fsnotify_mark_srcu);
524 spin_lock(&conn->lock);
525 if (conn->type == FSNOTIFY_OBJ_TYPE_DETACHED) {
526 spin_unlock(&conn->lock);
527 srcu_read_unlock(&fsnotify_mark_srcu, idx);
531 srcu_read_unlock(&fsnotify_mark_srcu, idx);
536 * Add mark into proper place in given list of marks. These marks may be used
537 * for the fsnotify backend to determine which event types should be delivered
538 * to which group and for which inodes. These marks are ordered according to
539 * priority, highest number first, and then by the group's location in memory.
541 static int fsnotify_add_mark_list(struct fsnotify_mark *mark,
542 fsnotify_connp_t *connp, unsigned int type,
545 struct fsnotify_mark *lmark, *last = NULL;
546 struct fsnotify_mark_connector *conn;
550 if (WARN_ON(!fsnotify_valid_obj_type(type)))
553 spin_lock(&mark->lock);
554 conn = fsnotify_grab_connector(connp);
556 spin_unlock(&mark->lock);
557 err = fsnotify_attach_connector_to_object(connp, type);
563 /* is mark the first mark? */
564 if (hlist_empty(&conn->list)) {
565 hlist_add_head_rcu(&mark->obj_list, &conn->list);
569 /* should mark be in the middle of the current list? */
570 hlist_for_each_entry(lmark, &conn->list, obj_list) {
573 if ((lmark->group == mark->group) &&
574 (lmark->flags & FSNOTIFY_MARK_FLAG_ATTACHED) &&
580 cmp = fsnotify_compare_groups(lmark->group, mark->group);
582 hlist_add_before_rcu(&mark->obj_list, &lmark->obj_list);
587 BUG_ON(last == NULL);
588 /* mark should be the last entry. last is the current last entry */
589 hlist_add_behind_rcu(&mark->obj_list, &last->obj_list);
591 mark->connector = conn;
593 spin_unlock(&conn->lock);
594 spin_unlock(&mark->lock);
599 * Attach an initialized mark to a given group and fs object.
600 * These marks may be used for the fsnotify backend to determine which
601 * event types should be delivered to which group.
603 int fsnotify_add_mark_locked(struct fsnotify_mark *mark,
604 fsnotify_connp_t *connp, unsigned int type,
607 struct fsnotify_group *group = mark->group;
610 BUG_ON(!mutex_is_locked(&group->mark_mutex));
616 * mark->connector->lock
618 spin_lock(&mark->lock);
619 mark->flags |= FSNOTIFY_MARK_FLAG_ALIVE | FSNOTIFY_MARK_FLAG_ATTACHED;
621 list_add(&mark->g_list, &group->marks_list);
622 atomic_inc(&group->num_marks);
623 fsnotify_get_mark(mark); /* for g_list */
624 spin_unlock(&mark->lock);
626 ret = fsnotify_add_mark_list(mark, connp, type, allow_dups);
631 fsnotify_recalc_mask(mark->connector);
635 spin_lock(&mark->lock);
636 mark->flags &= ~(FSNOTIFY_MARK_FLAG_ALIVE |
637 FSNOTIFY_MARK_FLAG_ATTACHED);
638 list_del_init(&mark->g_list);
639 spin_unlock(&mark->lock);
640 atomic_dec(&group->num_marks);
642 fsnotify_put_mark(mark);
646 int fsnotify_add_mark(struct fsnotify_mark *mark, fsnotify_connp_t *connp,
647 unsigned int type, int allow_dups)
650 struct fsnotify_group *group = mark->group;
652 mutex_lock(&group->mark_mutex);
653 ret = fsnotify_add_mark_locked(mark, connp, type, allow_dups);
654 mutex_unlock(&group->mark_mutex);
659 * Given a list of marks, find the mark associated with given group. If found
660 * take a reference to that mark and return it, else return NULL.
662 struct fsnotify_mark *fsnotify_find_mark(fsnotify_connp_t *connp,
663 struct fsnotify_group *group)
665 struct fsnotify_mark_connector *conn;
666 struct fsnotify_mark *mark;
668 conn = fsnotify_grab_connector(connp);
672 hlist_for_each_entry(mark, &conn->list, obj_list) {
673 if (mark->group == group &&
674 (mark->flags & FSNOTIFY_MARK_FLAG_ATTACHED)) {
675 fsnotify_get_mark(mark);
676 spin_unlock(&conn->lock);
680 spin_unlock(&conn->lock);
684 /* Clear any marks in a group with given type mask */
685 void fsnotify_clear_marks_by_group(struct fsnotify_group *group,
686 unsigned int type_mask)
688 struct fsnotify_mark *lmark, *mark;
690 struct list_head *head = &to_free;
692 /* Skip selection step if we want to clear all marks. */
693 if (type_mask == FSNOTIFY_OBJ_ALL_TYPES_MASK) {
694 head = &group->marks_list;
698 * We have to be really careful here. Anytime we drop mark_mutex, e.g.
699 * fsnotify_clear_marks_by_inode() can come and free marks. Even in our
700 * to_free list so we have to use mark_mutex even when accessing that
701 * list. And freeing mark requires us to drop mark_mutex. So we can
702 * reliably free only the first mark in the list. That's why we first
703 * move marks to free to to_free list in one go and then free marks in
704 * to_free list one by one.
706 mutex_lock_nested(&group->mark_mutex, SINGLE_DEPTH_NESTING);
707 list_for_each_entry_safe(mark, lmark, &group->marks_list, g_list) {
708 if ((1U << mark->connector->type) & type_mask)
709 list_move(&mark->g_list, &to_free);
711 mutex_unlock(&group->mark_mutex);
715 mutex_lock_nested(&group->mark_mutex, SINGLE_DEPTH_NESTING);
716 if (list_empty(head)) {
717 mutex_unlock(&group->mark_mutex);
720 mark = list_first_entry(head, struct fsnotify_mark, g_list);
721 fsnotify_get_mark(mark);
722 fsnotify_detach_mark(mark);
723 mutex_unlock(&group->mark_mutex);
724 fsnotify_free_mark(mark);
725 fsnotify_put_mark(mark);
729 /* Destroy all marks attached to an object via connector */
730 void fsnotify_destroy_marks(fsnotify_connp_t *connp)
732 struct fsnotify_mark_connector *conn;
733 struct fsnotify_mark *mark, *old_mark = NULL;
737 conn = fsnotify_grab_connector(connp);
741 * We have to be careful since we can race with e.g.
742 * fsnotify_clear_marks_by_group() and once we drop the conn->lock, the
743 * list can get modified. However we are holding mark reference and
744 * thus our mark cannot be removed from obj_list so we can continue
745 * iteration after regaining conn->lock.
747 hlist_for_each_entry(mark, &conn->list, obj_list) {
748 fsnotify_get_mark(mark);
749 spin_unlock(&conn->lock);
751 fsnotify_put_mark(old_mark);
753 fsnotify_destroy_mark(mark, mark->group);
754 spin_lock(&conn->lock);
757 * Detach list from object now so that we don't pin inode until all
758 * mark references get dropped. It would lead to strange results such
759 * as delaying inode deletion or blocking unmount.
761 objp = fsnotify_detach_connector_from_object(conn, &type);
762 spin_unlock(&conn->lock);
764 fsnotify_put_mark(old_mark);
765 fsnotify_drop_object(type, objp);
769 * Nothing fancy, just initialize lists and locks and counters.
771 void fsnotify_init_mark(struct fsnotify_mark *mark,
772 struct fsnotify_group *group)
774 memset(mark, 0, sizeof(*mark));
775 spin_lock_init(&mark->lock);
776 refcount_set(&mark->refcnt, 1);
777 fsnotify_get_group(group);
782 * Destroy all marks in destroy_list, waits for SRCU period to finish before
783 * actually freeing marks.
785 static void fsnotify_mark_destroy_workfn(struct work_struct *work)
787 struct fsnotify_mark *mark, *next;
788 struct list_head private_destroy_list;
790 spin_lock(&destroy_lock);
791 /* exchange the list head */
792 list_replace_init(&destroy_list, &private_destroy_list);
793 spin_unlock(&destroy_lock);
795 synchronize_srcu(&fsnotify_mark_srcu);
797 list_for_each_entry_safe(mark, next, &private_destroy_list, g_list) {
798 list_del_init(&mark->g_list);
799 fsnotify_final_mark_destroy(mark);
803 /* Wait for all marks queued for destruction to be actually destroyed */
804 void fsnotify_wait_marks_destroyed(void)
806 flush_delayed_work(&reaper_work);